from otree.api import (
    models, widgets, BaseConstants, BaseSubsession, BaseGroup, BasePlayer,
    Currency as c, currency_range
)
import random

doc = """
This is a task that requires real effort from participants.
Subjects are shown two images of incomprehensible text.
Subjects are required to transcribe (copy) the text into a text entry field.
The quality of a subject's transcription is measured by the
<a href="http://en.wikipedia.org/wiki/Levenshtein_distance">Levenshtein distance</a>.
"""


def levenshtein(a, b):
    """Calculates the Levenshtein distance between a and b."""
    n, m = len(a), len(b)
    if n > m:
        # Make sure n <= m, to use O(min(n,m)) space
        a, b = b, a
        n, m = m, n

    current = range(n + 1)
    for i in range(1, m + 1):
        previous, current = current, [i] + [0] * n
        for j in range(1, n + 1):
            add, delete = previous[j] + 1, current[j - 1] + 1
            change = previous[j - 1]
            if a[j - 1] != b[i - 1]:
                change = change + 1
            current[j] = min(add, delete, change)

    return current[n]


def distance_and_ok(transcribed_text, reference_text, max_error_rate):
    error_threshold = len(reference_text) * max_error_rate
    distance = levenshtein(transcribed_text, reference_text)
    ok = distance <= error_threshold
    return distance, ok


class Constants(BaseConstants):
    name_in_url = 'real_effort'
    players_per_group = None

    reference_texts = [
        "Revealed preference",
        "Hex ton satoha egavecen. Loh ta receso minenes da linoyiy xese coreliet ocotine! Senuh asud tu bubo tixorut sola, bo ipacape le rorisin lesiku etutale saseriec niyacin ponim na. Ri arariye senayi esoced behin? Tefid oveve duk mosar rototo buc: Leseri binin nolelar sise etolegus ibosa farare. Desac eno titeda res vab no mes!",
    ]

    num_rounds = len(reference_texts)

    allowed_error_rates = [0, 0.03]


class Subsession(BaseSubsession):
    pass


class Group(BaseGroup):
    pass


class Player(BasePlayer):
    transcribed_text = models.LongStringField()
    levenshtein_distance = models.IntegerField()